I got a very newbie question about ads

I want to monetize my website with ads (pop under / and on the side of the page) but i cant seem to understand this simple thing (sorry if I sound like i want to be spoon fed). From what i understand so far - I find a company that offers to pay me if traffic from my website clicks on their ad placed on my website. What I dont understand - do I chose what specific ads (niche) to place on my website, or does the company automatically adjust the ad for the user (depending on what he's been searching for example). lets say that my website is about wedding stuff and I want to monetize it with ads. what do I do?
- I see if the company has wedding related ads so my target audience will click
- or I just put the ad on what ever niche my website is about and it automatically adjusts
Thanks if you answer

There are lots of ways.

1. Adsense - Google advertiser network, you just copy paste the code and they change the ads accordingly. Google gets a portion of the revenue of the ads placed on your site.
2. Banner networks such as buysellads - Someone can see your offers, buys ad space, you approve his / her banner, everyone is happy.
3. You promote your own products or services. You keep 100% of the revenue.
4. You promote other people's product or services and you get a commission (affiliate marketing).

Each network has its own rules.
Each way has its benefits.

Well for most networks you will just put their code to your website and they will rotate their ads for your users. In some networks you can specify the niches of ads to be displayed.

If we are talking about pop-up/under you can choose categories of ads in most cases, but cannot choose specific ads/sites to be advertized.

Your right

You chose a company to join
And they have promotions you select the promotion and use a specail link each time a user press the link and go for a deal you get paid .

Usally best traffic is

Usa, Canada, uk , aus, scotland

Other traffic very low in cash ....

There other company's that do it as you said ,where there whole business surround one niche.

Popunders and popups are usally used .

You must be warned if you got a good website and it heigh indexed be carefull because google ban websites using any popups in any style.

But if it a landing page just for sales any method is fine.

Good luck